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H. P. & F. H. BROWN.

ARTIFICIAL ELECTRICAL RESISTANCE.

No. 347,766. Patented Aug. 24, 1886.

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Enroll P.3 Earns HerZeTZBwm Y Witnesses: 4

UNITED STATES PATENT OFFICE.

HAROLD P. BROWN AND FRANCIS HERBERT BROIVN, OF CHICAGO, ILL.

ARTIFICIAL ELECTRICAL RESISTANCE.

SPECIFICATION forming part of Letters Patent No. 347,766, dated August 2 1886.

Application filed March 6, 1886. Serial No. 19!,102.

T0 aZZ whom it may concern:

Be it known that we, HAROLD P. BROWN and FRANCIS HERBERT BROWN, citizens of the United States, residing in Chicago, in the county of Cool; and State of Illinois, have invented a new and useful Improvement in Artificial Electrical Resistances, of which the following is a specification.

Our invention relates to artificial electric resistances for rheostats, current-regulators, &c.

Vi e have discovered by experiment that a very cheap and efficient electric resistance may be formed out of small pieces of metal of a regular or irregular shape piled togetheras, for example, short straight pieces of wire laid one on top of another, or iron chips or shavings-as, for example, those from a latheor small pieces of iron of a spherical or other shape piled together in a suitable inclosing case or box. The degree of resistance may be varied by making the metal pieces smaller or larger, and also by varying the pressure upon the pile, or its area in crosssection. Iron is the preferable metal to use and the glaze which is usually found upon wire should be removed by heating to a bright red, or baking, or otherwise, when short pieces of wire are used. The resistancepile may be divided into parts by contact plates or pieces inserted at intervals, with one or the other of which the circuit-wires may be connected, according to the amount of rcsistan ce desired to be placed in the circuit.

\Ve are of course aware that coils of wire have heretofore been used for resistance; but we find that a much less amount of wire will produce the same resistance when it is cut up into short pieces, and such pieces piled one on top of another.

\VllCl'C it is desired to facilitate the escape of heat, the resistance-piles should be provided with ventilating-passages in and through them.

In the accompanying drawings, which form a part of this specification, and in which similar letters of reference indicate like parts. Figure 1 is a front elevation of a resistancepile embodying our invention. Fig. 2 is a section on line 2 2 of Fig. 1. Fig. 3 is a detail view showing as a modification the small metal (No model.)

pieces in the form of balls, and Fig. l is a View showing a modification wherein iron filings are used.

In said drawings, A represents abox or case, preferably of iron, furnished with slate or other insulating-lining, B.

O O are small fine pieces of metal piled to gether, preferably short pieces of iron wire from which the glaze has been removed, con stituting the resistance. At intervals contact plates or pieces 1) D are or may be inserted, with which the circuit-wires E E may be connected.

F is a screw, the end of which bears against the movable plate 13' at the top of the resist ance-pile, and by which the pressnrenpon the pile may be regulated and the resistance thereby adj nstcd. The resistance may also be adjusted by varying the crosssectional area of the mass or pile of resistance pieces.

XVe clain1- l. The artificial resistance, consisting in a pile of short pieces of wire placed one on top of another, substantially as specified.

2. The artificial electric resistance, consisting in a mass or pile composed of a great number of small fine pieces of metal piled together in contact with each other, having contact plates or pieces inserted at intervals, substantially as specified.

The artificial resistance, consisting in a pile of short pieces of wire placed one on top of another, having contact plates or strips inserted at intervals, substantially as specified.

4. The artificial resistance, consisting in a pile of short pieces of wire placed one on top of another, having contact plates or strips inserted at intervals, in combination with case A, having lining B, of insulating material, substantially as specified.

5. The artificial resistance, consisting in a pile of small fine pieces of metal having contact plates or strips inserted at intervals, in combination with case A, having insulatinglining B, substantially as specified.

HAROLD P. BROlVN. FRANCIS HERBERT BROIVN.

\Vi tnesses:

H. M. MUNDAY, J OHN WV. llIUNDAY. 

